Sex differences in stretch-induced hypertrophy, maximal strength and flexibility gains

Abstract

Introduction: If the aim is to increase maximal strength (MSt) and muscle mass, resistance training (RT) is primarily used to achieve these outcomes. However, research indicates that long-duration stretching sessions of up to 2 h per day can also provide sufficient stimuli to induce muscle growth. In RT literature, sex-related differences in adaptations are widely discussed, however, there is a lack of evidence addressing the sex-related effects on MSt and muscle thickness (MTh) of longer duration stretch training. Therefore, this study aimed to investigate the effects of 6 weeks of daily (1 h) unilateral static stretch training of the plantar flexors using a calf-muscle stretching device.Methods: Fifty-five healthy (m = 28, f = 27), active participants joined the study. MSt and range of motion (ROM) were measured with extended and flexed knee joint, and MTh was investigated in the medial and lateral heads of the gastrocnemius.Results: Statistically significant increases in MSt of 6%–15% (p < .001–.049, d = 0.45–1.09), ROM of 6%–21% (p < .001–.037, d = 0.47–1.38) and MTh of 4%–14% (p < .001–.005, d = 0.46–0.72) from pre-to post-test were observed, considering both sexes and both legs. Furthermore, there was a significant higher increase in MSt, MTh and ROM in male participants. In both groups, participants showed more pronounced adaptations in MSt and ROM with an extended knee joint as well as MTh in the medial head of the gastrocnemius (p < .001–.047). Results for relative MSt increases showed a similar result (p < .001–.036, d = 0.48–1.03).Discussion: Results are in accordance with previous studies pointing out significant increases of MSt, MTh and ROM due to long duration static stretch training. Both sexes showed significant increases in listed parameters however, male participants showed superior increases.

Effects of exercise of different intensities on withdrawal symptoms among people with substance use disorder: a systematic review and meta-analysis

“…The involvement of key neural systems (dopamine, μ opioid receptors, kappa opioid receptors, and brain-derived neurotrophic factor) in addiction and withdrawal differs greatly between male patients and female patients, which could explain the gender differences in clinical symptoms and treatment efficacy during withdrawal ( Becker and Chartoff, 2019 ). Moreover, a recent study has shown that gender differences also exist in exercise-induced hypertrophy and gains in maximal strength and flexibility ( Warneke et al, 2022 ). Taken together, the possibility of gender differences in exercise-induced improvement in withdrawal symptoms should be a significant concern.…”

P077 Upskilling rheumatology therapists in work rehabilitation: an evaluation of the Workwell training programme

“…Lastly, during our pilot testing, we observed that the vertical shin and neutral ankle angle adopted during the bilateral version of the SIPFT [11,[13][14][15][16][17]20] led to the ball of the foot being placed anterior to the contact point between the bar of the rig and the thighs. This is an issue when using single-axis-only force plates (i.e., those that record vertical forces only, which is typical of commercial-grade force plates), as the point of force application (i.e., the ball of the foot) is in front of the bar-thigh interface, which induces a large anterior-posterior force application that cannot be recorded with single-axis force plates.…”

“…Half of surveyed strength and conditioning coaches working in football use force plates to regularly assess the force-generating capabilities of their athletes [10]. Force plates have only been used to assess isometric plantar flexion force in studies published since 2022 [11][12][13][14][15][16][17][18][19][20]. Only one study involved football players and included the seated isometric plantar flexor test (SIPFT) to determine its reliability of quantifying peak force [20].…”

“…Despite the abovementioned limitations of the SIPFT protocol utilized by Rhodes et al [20], several other researchers have adopted a similar approach to assessing the isometric peak force capabilities of the plantar flexors [11,[13][14][15][16][17]19]. An alternative approach to conducting the SIPFT, whereby a novel device specifically designed to assess the isometric force capabilities of the plantar flexors was validated [18] and used to assess a large cohort of rugby players, was recently published, thus providing normative reference values [12].…”

Minimalist Training: Is Lower Dosage or Intensity Resistance Training Effective to Improve Physical Fitness? A Narrative Review

“…Furthermore, the authors tested the effectiveness of 10 minutes’ daily stretching using a stretching board, and were still able to induce significant increases in muscle strength [ 165 ]. The literature investigating stretch-mediated (≥ 30 min per session) hypertrophy is very scarce and has exclusively tested the plantar flexors [ 163 , 166 , 167 , 169 , 170 ]. More research is necessary to address the optimal dose–response relationship with more muscles and diverse participants.…”